This is a testharness.js-based test.
[FAIL] Service worker registration from signed exchange
  assert_equals: expected (undefined) undefined but got (string) "SecurityError: Failed to register a ServiceWorker for scope ('https://web-platform.test:8444/signed-exchange/resources/scope/https://web-platform.test:8444/signed-exchange/resources/register-sw-from-sxg.html') with script ('https://web-platform.test:8444/signed-exchange/resources/service-worker.js'): No URL is associated with the caller's document."
Harness: the test ran to completion.